The invention concerns a separation system for a potato harvesting machine or a preparation machine for root crop or similar crop for separating crop from a mixture with clods, rocks, and similar solid bodies, comprising a conveying device supplying the substantially compact mixture as a conveyed stream, from where the mixture, moved into the area of at least one drop stage and, in the process, influenced by means of a conveying medium in the form of an air stream can be separated such that at least the crop as well as the solid bodies, can be further conveyed and discharged from the separation device as individuals separated goods, respectively.
For separating potatoes or similar crop from a mixture with clods, rocks, and similar solid bodies, different concepts of separation systems are known in which the crop mixture can be influenced in a conveying phase by means of an additional air stream. In DE 747 316 a device is proposed that guides the mixture into an air channel so that, in its longitudinal extension, the crop in the form of potatoes is further advanced and the comparatively heavy solid bodies can be discharged through a bottom trap. In a device according to DE 854 597, the mixture is directly loaded by an air stream so that sorting of the components of different weight is realized in accordance with a trajectory.
The constructions according to DE 908 808 and DE 928 017 show respective conveying belts on which the mixture by means of a tangential air stream can be separated into the individual parts. In a similar construction according to DE 1 607 628, a conveying stretch is defined by means of respective conveying rollers with contours meshing tooth-like with each other so that an air stream which is vertical thereto effects a mixture separation. In a rock separating system according to DE 26 22 277, a vibrating rubber belt is utilized onto which the mixture is supplied and, in the process, the tubers under the effect of an air stream are conveyed farther at the top side. The comparatively heavy rocks or similar admixtures can pass through the rubber belt and are separated in this way from the crop.
DE 28 31 051 describes a potato harvesting machine in which a nozzle-shaped blower is directed onto a transport belt conveying away the haulm components. A similar construction is shown in DE 35 29 416 wherein, below the supply of the mixture, a blower is directed onto the sorting belt. DE 77 04 826 also provides a conveying belt which receives the mixture wherein a blower effecting separation is oriented opposite to its conveying direction. In the solutions according to DD 3516, DD 206 884, and DD 210 847, there are respective multi-stage separation systems for root crop which interact with an air stream in a sorting phase. According to EP 0 613 615, the falling mixture is exposed to an air stream in such a way that in particular the haulm components are forced into a receiving slot between two transport rollers and the thus individualized potatoes are moved farther due to their weight.
According to GB 636,100, a generally known blower channel is utilized in which at the end a flap is provided that deflects the sorted goods, and in a solution according to GB 711,984 the venting action is oriented such that in the area of a cascade-like arranged construction the air stream is acting toward respective compartments and fills the latter with different components of the mixture that has been separated in this way. A similar construction is disclosed in U.S. Pat. No. 4,515,276 wherein a mixture of crop and rocks fall onto an endless conveyor belt and, in the process, an additional air stream is acting as a separation aid. The separation of the parts is realized in that in the area of the conveying belt a gravitation layering process detaches the heavier from the lighter materials and these two “layers” can be conveyed away by a “rolling movement” and a conveying belt movement in different directions.
According to DD 204 829 a construction is proposed in which the crop is removed by suction from the mixture, and in DD 217 400 the mixture components which are moved on a conveyor belt are classified by means of a sensor system and subsequently discharged in sorted lots.
The invention concerns the problem of providing a separation system for a potato harvesting machine or similar machines for processing root crop by means of which the separation of the crop from the mixture is realized at higher throughput performance, wherein with separation conditions that can be optimized a crop can be conveyed away that is free of contaminants and free of product damage, and wherein the system as a whole enables a reduction of the energy expenditure.